Frost dates for 53024Grafton, WI
The average last spring frost in Grafton is April 23 and the average first fall frost is October 24, giving a typical growing season of about 182 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 23
- Average first fall frost
- Oct 24
- Growing season
- 182 days
Safer after May 9 (1-in-10 risk)
Possible by Oct 8 (1-in-10 risk)
Last frost typically in 178 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 20 · May 5 · May 23 | Sep 27 · Oct 11 · Oct 26 | 156 days | 100% |
| Frost / freeze (32°F) | Apr 10 · Apr 23 · May 9 | Oct 8 · Oct 24 · Nov 5 | 182 days | 100% |
| Hard freeze (28°F) | Mar 31 · Apr 11 · Apr 24 | Oct 21 · Nov 2 · Nov 15 | 205 days | 100% |
Planting calendar for Grafton
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 23 – May 29 |
| Tomatoes | Transplant outdoors | May 9 – Jul 4 |
| Peppers | Start seeds indoors | Mar 23 – Apr 23 |
| Peppers | Transplant outdoors | May 23 – Jun 23 |
| Eggplant | Start seeds indoors | Apr 9 – May 8 |
| Eggplant | Transplant outdoors | May 23 – Jun 23 |
| Cucumbers | Sow outdoors | May 23 – Jul 14 |
| Summer squash | Sow outdoors | May 9 – Jun 23 |
| Winter squash & pumpkins | Sow outdoors | May 23 – Jun 23 |
| Snap beans | Sow outdoors | May 9 – Aug 6 |
| Sweet corn | Sow outdoors | May 9 – Jul 4 |
| Watermelon & cantaloupe | Sow outdoors | May 23 – Jun 23 |
| Okra | Sow outdoors | May 16 – Jun 8 |
| Peas | Sow outdoors (spring) | Mar 23 – May 8 |
| Potatoes | Plant outdoors (spring) | Mar 23 – May 23 |
| Onions | Start seeds indoors (spring) | Feb 9 – Mar 8 |
| Onions | Transplant outdoors (spring) | Apr 9 – May 8 |
| Broccoli | Start seeds indoors (spring) | Mar 5 – Apr 8 |
| Broccoli | Transplant outdoors (spring) | Apr 9 – May 8 |
| Broccoli | Start seeds indoors (fall) | Jun 24 – Jul 4 |
| Broccoli | Transplant outdoors (fall) | Jul 24 – Aug 4 |
| Cabbage | Start seeds indoors (spring) | Feb 23 – Mar 23 |
| Cabbage | Transplant outdoors (spring) | Mar 23 – Apr 23 |
| Cabbage | Start seeds indoors (fall) | Jun 14 – Jul 14 |
| Cabbage | Transplant outdoors (fall) | Jul 14 – Aug 14 |
| Leaf lettuce | Sow outdoors (spring) | Mar 23 – Jun 8 |
| Leaf lettuce | Sow outdoors (fall) | Jul 14 – Aug 30 |
| Spinach | Sow outdoors (spring) | Mar 16 – Apr 29 |
| Spinach | Sow outdoors (fall) | Jul 31 – Sep 4 |
| Radishes | Sow outdoors (spring) | Mar 23 – May 13 |
| Radishes | Sow outdoors (fall) | Jul 14 – Sep 14 |
| Kale | Sow outdoors (spring) | Apr 9 – Apr 29 |
| Kale | Sow outdoors (fall) | Jul 7 – Aug 14 |
| Carrots | Sow outdoors (spring) | Apr 23 – Jun 8 |
| Carrots | Sow outdoors (fall) | Jun 14 – Jul 30 |
| Garlic | Plant outdoors (fall) | Oct 14 – Nov 14 |
Where these dates come from
ZIP code 53024 is matched to the NOAA station Grafton Wwtp, WI, 1.7 km away, at 741 ft elevation (13 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Grafton Wwtp, WI (used) | 741 ft | Apr 23 | Oct 24 |
| Saukville Wwtp, WI | 766 ft | May 5 | Oct 11 |
| Port Washington, WI | 594 ft | Apr 27 | Oct 22 |
| West Bend, WI | 940 ft | May 4 | Oct 11 |
Frost dates near Grafton
- Cedarburg, WI 53012 · last May 6, first Oct 8
- Saukville, WI 53080 · last Apr 27, first Oct 22
- Mequon, WI 53097 · last May 6, first Oct 8
- Port Washington, WI 53074 · last Apr 27, first Oct 22
- Newburg, WI 53060 · last May 4, first Oct 11
- Jackson, WI 53037 · last May 6, first Oct 8
- Fredonia, WI 53021 · last May 3, first Oct 16
- Germantown, WI 53022 · last May 6, first Oct 8
Frequently asked questions
- When is the last frost in Grafton, WI?
- For ZIP code 53024, the average last spring frost (32°F) is April 23, based on NOAA 1991-2020 climate normals for the Grafton Wwtp, WI weather station. There is a 1-in-10 chance of a frost after May 9.
- When is the first frost in Grafton, WI?
- The average first fall frost (32°F) is October 24. There is a 1-in-10 chance of frost by October 8, so tender plants are at risk from that point on.
- How long is the growing season in 53024?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 182 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.